In the short run, O a. at least one of the firm's inputs is fixed O b. customer tastes and preferences are fixed O c. the firm may vary all inputs O d. sunk costs are variable O e. government intervention is inevitable If a firm is experiencing diminishing marginal returns to labor, then a. total output must be decreasing O b. total output rises more slowly as additional workers are added O c. the firm must decrease the amount of labor it hires O d. total output per worker must be rising O e. the firm must be operating in the long run